What is the relationship between the motor service coefficient and the working system? What performance can the motor service coefficient reflect?

As a parameter that motor users are more concerned about, the service coefficient can reflect the performance of the motor. Today, let’s briefly analyze what the motor service coefficient is? How to reflect the performance of the motor?

The motor service factor (SF: Service Factor) indicates the maximum load rate that allows the motor to operate continuously for a long time. It is a parameter that measures the continuous load working ability of the motor. It is a spare overload rate to meet special applications. The value is the maximum allowable The ratio . The working mode is the operating mode and should not be confused with the capacity coefficient.

For example: If it is a 10KW motor, if the coefficient service is 1.15, then its actual maximum output power is 10×1.15=11.5KW

The common working systems of motors include S1 continuous working system, S2 short-time working system, and S3~S7 periodic working system. Uncommon ones include S8 continuous periodic working system with variable speed and load, and S9 non-periodic changing load and speed working system. When the operating mode does not match any of the standard modes S1 to S9 working system, and the motor is required to operate continuously with variable load, the motor performance can be constrained and characterized by a combination of "S1 continuous working system + service factor" and other combinations. Although the combination of "working system + service factor" is actually a working system, it cannot be said that the service coefficient is a working system.

The service factor is a comprehensive indicator, numerically equal to the maximum overload rate. According to the operating characteristics of three-phase asynchronous motors, the service factor is generally stipulated as 1.15-1.25. Because using a low service factor, there is actually no substantial application performance; the service factor is too high, and the economical operation of the motor is not ideal.

In short, only by making good use of the "service coefficient" of the motor can the motor operate within the specified and reasonable range. Otherwise, the initial design of the motor will inevitably deviate from the actual load condition, and the motor's performance may not be fully exerted or it may not be capable of "full load" long-term continuous operation.